Whooping cough spreads very easily from person to person. Because it usually starts off like a cold, people who have whooping cough may not know they’re spreading it. And it can be deadly, especially for newborn babies.

Babies who get whooping cough can have dangerous complications, like pneumonia (lung infection), convulsions (uncontrolled shaking), and brain damage. That’s why it’s especially important for pregnant women to get vaccinated — and that people who spend time with babies are up to date on their whooping cough vaccine.

Side effects are usually mild and go away in a few days. They may include:

Pain, swelling, or redness where the shot was given

Fever

Headache

Feeling tired or irritable

Upset stomach, throwing up, and diarrhea (watery poop)

Not feeling hungry

Fussing (in children)

It’s very rare, but the DTaP vaccine can also cause the following symptoms in children:

Seizures (about 1 child in 14,000)

Non-stop crying, for 3 hours or more (up to about 1 child in 1,000)

Fever higher than 105°F (about 1 child in 16,000)

Like any medicine, there's a very small chance that whooping cough vaccines could cause a serious reaction. Keep in mind that getting a whooping cough vaccine is much safer than getting whooping cough. Learn more about vaccine side effects.